Subtropical anticyclone impacts life-history traits of a marine top predator
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Subtropical anticyclones are semi-permanent high-pressure systems located in all the major ocean basins and associated with large-scale wind and weather conditions. These systems structure the physical environments for many wildlife species, affecting ecosystem productivity, yet, their demographic impacts on wildlife species remain unexplored. Hence, it is necessary to understand whether these large-scale systems can drive critical life-history traits. Using 39 years of long-term monitoring data, we demonstrate that variability in the Indian Ocean subtropical anticyclone, the Mascarene High, affects the survival and reproduction of a marine top predator, the wandering albatross ( Diomedea exulans ). Climate analysis reveals the mechanisms behind this effect: an intensified and poleward-shifted Mascarene High enhances westerly winds, creating favorable wind conditions that increase vital rates across the entire life cycle of wandering albatrosses, including juveniles and adults, females and males. By integrating climate analyses with demographic processes, this study highlights how characteristics of subtropical anticyclones offer new insights into the influence of large-scale atmospheric features on species responses, advancing our understanding of the effects of climate variability and change on biodiversity.
Significance
Winds influence the movement and energy use of many species. Subtropical anticyclones shape wind patterns in subtropical regions, potentially influencing wildlife population dynamics. However, we lack direct evidence linking subtropical anticyclones to the survival and reproductive rates of wildlife species. We show that an intensified and poleward-shifted Indian Ocean subtropical anticyclone enhances westerly winds, improving the survival and reproduction of wandering albatrosses, “the wind rider”, breeding in the southern Indian Ocean. Our findings underscore the value of tracking subtropical anticyclone characteristics as climate indices for linking regional wind conditions to demography, providing key insights into the impacts of global change on wildlife.
